On 20 December 1999, David W. Tamkin <dattier(_at_)mcs(_dot_)net> wrote:
Steve Youngs asked,
| Lock files, basically, they confuse the fsck out of me. :-(
| Can someone enlighten me as to:
| What are the different types?
Global and local. When we speak of a "regional" lockfile, we mean a
global one of limited scope.
True, but lockfiles (a.k.a. "dotlocks") are only the procmailrc side
of the story, and they will only keep procmail from stepping of its
own toes. Most systems have other mechanisms too of "locking" files
--- fcntl, lockf, flock, mandatory kernel locks etc. --- which are not
equivalent, and which may or may not act exclusively to one another.
In order to prevent the bad things from happening, you need to make
sure _all_ programs that might want to write to the same file (f.i.
your MUA, your MTA and procmail) agree on at least one of these locking
strategies. Now, if you don't have privileges to install software on
the machine you're using as a mail gateway, there's little you can do to
change this --- but most programs will at least tell you what locking
methods they are using (see f.i. "procmail -v"), so you can complain to
your sysadmin if you find discrepancies.
Dr. Liviu Daia e-mail: Liviu(_dot_)Daia(_at_)imar(_dot_)ro
Institute of Mathematics web page: http://www.imar.ro/~daia
of the Romanian Academy PGP key: http://www.imar.ro/~daia/daia.asc